(a) Field of the Invention
The present invention relates to liquid crystal displays (LCDs), and in detail, to a method for improving display quality and viewing angle of LCDs.
(b) Description of the Related Art
An LCD includes two panels provided with field-generating electrodes, and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer, which determines orientations of LC molecules in the LC layer to adjust polarization of incident light.
In an LCD, usually, red, green, and blue color filters are sequentially disposed. Color images are displayed by controlling intensity of light which passes through the color filters.
However, there are limitations in displaying full colors by using three color filters.
Recently, as LCDs have been gaining popularity as multi-media displays, the need for good color reproducibility has increased. Especially, when an LCD is used as a television, good color reproducibility is extremely important.
When color reproducibility is discussed, the green color is important. The green color of the National Television Standards Committee (NTSC) is marked at x=0.21, y=0.70 on color coordinates of the International Commission of Illumination (CIE). However, the green light from the conventional green color filter of an LCD television having a thickness of 1.9 μm is marked at x=0.275, y=0.60 on the CIE color coordinate system.
When the conventional green color filter is used, the color reproducibility reaches only up to 72% of natural color. If one wishes to make a green color filter producing green color of NTSC which allows color reproducibility of 80% to 100%, one of the following two methods may be used. The first is increasing the dispersion density of pigments in the color filter, and the second is increasing the thickness of the color filter. However, when the dispersion density of pigments in the color filter is increased, stability of the photoresist of the color filter is degraded. When the thickness of the color filter is increased, the color filter needs to have a thickness of about 7.6 μm, which is four times thicker than that of the normal color filter. This causes difficulty in forming the color filter.